IMAGE QUALITY AND RADIOGRAPHIC QUALITY Flashcards
(127 cards)
1
Q
what are the 2 ways of shape distortion
A
- elongation
2. foreshortening
2
Q
influence the total amount of magnification of the image
A
SID
3
Q
TRUE OR FALSE: size distortion always occur in OID
A
TRUE
4
Q
refers to the actual size of an object compared with its true actual size
A
magnification
5
Q
results from radiographic misinterpretation of either the size (magnification) of the shape of the anatomic part
A
distortion
6
Q
TRUE OR FALSE: patient increase the amount of unsharpness in an image
A
true
7
Q
TRUE OR FALSE: greater spatial resolution minimizes sharpness of the anatomic structure
A
false, minimizes unsharpness
8
Q
refers to the smallest object detected in an image
A
spatial resolution
9
Q
is termed used to evaluate the accuracy of the recorded anatomic structural line
A
spatial resolution
10
Q
refers to the range of visible densities
A
scale of contrast
11
Q
is used to describe the ability of an image receptor to distinguish between objects having similar subject contrast
A
contrast resolution
12
Q
TRUE OR FALSE: contrast is subjective
A
true
13
Q
TRUE OR FALSE: brightness + density = unmeasurable
A
false, measurable
14
Q
what are the three factors that contribute to subject contrast
A
tissue thickness
density
atomic number
15
Q
refers to the absorption characteristics of the anatomic tissue imaged and the quality of x-ray beam
A
subject contrast
16
Q
TRUE OR FALSE: an object that has sufficient brightness but no differences appears to heterogenous object
A
false, homogenous
17
Q
is the difference in the brightness levels or densities
A
radiographic / image contrast
18
Q
TRUE OR FALSE: differential absorption is the same for both digital and film screen image receptors
A
true
19
Q
what are the 2 types of image receptors
A
- digital
2. film screen
20
Q
anatomic tissue that varies in absorption and transmission creates what shade of color ____
A
gray / dark and light areas
21
Q
TRUE OR FALSE: x-ray photons that are transmitted = black areas (decreased brightness)
A
true
22
Q
TRUE OR FALSE: absorb incoming x-ray photons (photoelectric effect) = white / clear (increase brightness)
A
true
23
Q
TRUE OR FALSE: absorb incoming x-ray photons (photoelectric effect) = white / clear (increase brightness)
A
true
24
Q
an unwanted exposure created by scattered radiation
A
fog
25
when the unwanted beam leave the patient; transmitted and scattered
exit radiation / remnant radiation
26
the quality of image is compromised
scattered radiation
27
TRUE OR FALSE: absorption + transmission = image that structurally represent the anatomic part
true
28
it is when an incoming x-ray photons passes through anatomic part without any interaction with the anatomic structure
transmission
29
beam attenuation ___ with higher x-ray beam, and ___ with lower x-ray beam
decrease, increase
30
determines the energy or penetrability of x-ray photon, and effects in the attenuation of anatomic tissue
kilovoltage
31
TRUE OR FALSE: high- penetrating x-ray are more likely to be absorbed
true
32
TRUE OR FALSE: low penetrating x-ray are more likely to be absored
true
33
lower penetrating x-ray = ____ wavelength
longer
34
higher penetrating x-ray = ____ wavelength
shorter
35
refers to the quality of the x-ray beam or its penetrating ability
x-ray beam quality
36
atomic number for fat
6.3
37
atomic number for bones
13.8
38
TRUE OR FALSE: more x-rays = thicker anatomical part
true
39
for every 4-5 cm (1.6-2in) of tissue thickness, how many percent must be reduced in x-ray attenuation
50%
40
TRUE OR FALSE: x-rays are exponentially attenuated
true
41
increase in thickness, ___ beam beam attenuation either absorption or scattering
increase
42
4 factors of x-ray beam attenuation
1. thickness of anatomical part
2. atomic number
3. tissue density
4. energy of the x-ray beam
43
TRUE OR FALSE: scattered photons leave the patient and does not strike the image receptor = radiation exposure near the patient
true
44
TRUE OR FALSE: scattered photons absorbed = radiation exposure of the patient
true
45
is an interaction that occurs with low-energy x-rays, typically below the diagnostic range; x-ray does not lose energy but changes direction
coherent scattering
46
TRUE OR FALSE: higher kVp decreases the percentage of Compton effect
false, increase percentage
47
TRUE OR FALSE: higher kVp decreases the overall number of x-ray interactions within matter because of the increased photon transmission
true
48
TRUE OR FALSE: more simple atoms, more opportunities for interaction
false, complex atoms
49
TRUE OR FALSE: less energy = less wavelength
false, more
50
takes the electron at the inner part of the shell
photoelectric effect
51
takes the electron at the outer part of the shell
Compton effect
52
TRUE OR FALSE: compton interaction only depends on the energy of the incoming photon, and not the atomic # and anatomic tissue
true
53
also known as ejected electron
secondary electron
54
causes secondary exposure
compton effect
55
the result from the incoming x-ray photon changing / loses energy and changes direction
compton effect
56
the incoming photons are not absorbed but instead lose energy during interactions with the atoms comprising tissue
scattering
57
TRUE OR FALSE: after absorption, overall energy or quantity of the primary beam decreases
true
58
the probability of the total photon absorption by the photoelectric effect depends on the ____ of the incoming x-ray and the ___ of the anatomical tissue
energy, atomic #
59
an interaction with matter
photoelectric effect
60
is responsible for the total absorption
photoelectric effect
61
is a characteristics of x-ray and the ability to remove *(eject) electrons
ionization
62
occurs when it has enough energy to remove (eject) an inner shell electron
absorption
63
also know as ejected electron
photoelectron, secondary electron
64
total absorption of energy by atoms
absorption
65
occurs as the result of the photo interactions with the anatomic structures that comprises the tissue
beam attenuation
66
is the reduction in the intensity or number of photons in the primary x-ray beam
beam attenuation
67
3 process required by differential absorption
1. beam attenuation
2. absorption
3. transmission
68
an anatomic part where it absorbs more photons than parts filled with air
bone
69
is a process whereby some amount of x-ray beam is absorbed in the tissue and some passes through (transmits) the anatomic part
differential absorption
70
TRUE OR FALSE: attributes of a quality radiograph are similar regardless of the type of imaging system
true
71
is produced following the processing of the latent or invisible image
manifest image / visible radiographic image
72
what is the atomic # for the element, Calcium?
20
73
what is the most common dense element in the body?
calcium
74
TRUE OR FALSE: radiation that exits the patient is composed of varying energies and interacts with image receptor
true
75
what are the 3 absorption characteristics of the anatomic part
thickness
atomic number
tissue density / compactness
76
TRUE OR FALSE: does quantity and quality of the primary beam affects its interactions within the various tissues that makeup atomic parts?
true
77
a device that receives the radiation leaving the patient
image receptor (IR)
78
is sometimes required to elongate a part so that a particular anatomic structure can be visualized better
CR angulation
79
is the term typically used when referring to noise on a film image
quantum mottle
80
caused by phosphor crystal size
structure noise
81
decrease amount of photon, ___ the amount of quantum noise within the radiographic image
increase
82
increasing number of photos, ____ the amount of quantum noise within the radiographic image
decrease
83
ALARA
as low as reasonably achievable
84
unwanted image on a radiograph
image artifact
85
2 types of digital IR
computed radiography
| direct radiography
86
houses the imaging plate
casette
87
it is where the latent image is stored
phosphor
88
IRs can be portable or fixed, and uses imaging plate
computed radiography
89
IRs have self-scanning readout mechanism, employs an array of x-ray detectors that receive the exit radiation and convert the varying x-ray intensities into proportional electronic signals for digitization
direct radiography
90
active layer of the fim, heart of the film
emulsion
91
most widely used radiographic fil
screen film
92
refer to a physical imperfections
sensitivity speck
93
refers to the ability of radiographic film to provide a certain level of image contrast (density differences)
film contrast
94
refers to the color of light produced by a particular intensifying screen, caused by intensifying screens
spectral sensitivity
95
a device found in radiographic cassettes that contains phosphor to convert x-ray energy into light
intensifying screen
96
is the emission of light from the screen when stimulated by radiation
luminescence
97
the emission of light after x-ray exposure has terminated; cause unwanted exposure to the film
phosphorescence
98
the use of such screens allows the radiographer to use considerable lower mAs values
screen speed
99
x-ray tube to patient
sod
100
patient to IR
oid
101
x-ray tube to image receptor
sid
102
it is the responsibility of the radiographer to limit x-ray beam field size; limiting the patient exposure and the amount of scatter radiation
beam restriction
103
a most commonly used beam restricting device, most sophisticated, useful, accepted type of beam restricting device
collimator
104
refers to a decrease in size of the projected radiation field
collimation or beam restriction
105
simplest type of beam- restricting device; is a flat piece of lead that contain a hole
aperture diaphragm
106
are shaped differently; is essentially an aperture diaphragm that has an extended flange attached to it
cones and cylinders
107
is most useful compared to cones
cylinders
108
referred to beam restriction accomplished with the use of collimator
collimation
109
how many blades does a collimator have
2 or 3 lead shutters
110
also called as the positive beam restricting device; automatically limits size and shape of the primary beam
automatic collimator
111
who invented the radiographic grid
gustave bucky
112
what year was radiographic grid invented
1913
113
is a device consisting of very thin lead strips with radiolucent interspaces intended to absorb scatter radiation emitted from the patient
radiographic grid
114
what is grid made of
aluminum
115
precise height, thickness, space between radiographic grid
grid construction
116
expresses the number of lead lines per unit length
grid frequency
117
is defined as the ratio of the height of lead strips to the distance between them
grid ratio
118
refers to the linear pattern of the lead lines of a grip
grid pattern
119
grids that run in only one direction
linear grip
120
grids that run in right angles
cross grid, cross hatched grid
121
refers to the orientation of the lead lines relative to one another
grid focus
122
grids that run parallel to one another
parallel grid
123
has lead lines that are angled, or canted to approximately match the angle of divergence of the primary beam
focused grid
124
has lead lines that are angled, or canted to approximately match the angle of divergence of the primary beam
focused grid
125
is defined as the amount of luminescence
brightness
126
refers to the amount of overall blackness on the processed image
density
127
refers to the variations in brightness and density
contrast
